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warren hiatus tartar oneness. BELL, or new YORK, n. Y, ASSlGNOR. To run BELLTYPE nnenAvINe COMPANY, (LIMITED,) or SAME PLACE.

eaoro eeraer threesome] s'rnorrrcs'rron forming part of Letters Patent to. assets, dated April 13, 1680.

Application filed January 5, 1880.

State of New York, have invented certain new and useful Improvements in Photo-Relief Engraving; and I do hereby declare the following to be a fuli, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use it.

My invention relates to a process of preparing negatives for photo-relief engraving.

The object is to' provide improved means for directly photographing any' suitable object without necessity of making .a preliminary drawing in wash or linc..the'reof To this end theinvention consists in a process having the following steps: first, photographing a negative of the object to be engraved; second, printing a positive therefrom on asurfaceprovided with raiseddots or points, which latter have their upper portions coated with a sensitizing substance, while the remaining portion of the surface is free from the sensitizing substance; third, photographing a negative from said positive.

To form the raised dots or points on the photographic surface, I form a plate of metal or other suitable substance with a granulated,

raised, perforated, or abraded surface of greater or less fineness, according to the character of the engraving to be produced, said rough encd or perforated surface being formed by etching, stamping, or in any other desired way, the object being to produce an innumerable number of small raised points or projections,

which may be formed on said plate in plain arrangement, or in designs and figures-of any kind.

The surface which is to receive the positive print may be hard-surfaced paper or other suitable material. I may apply thereto awash or coat'of any suitable pigment, such as Ghinese or flake white, mixed with a solution of albumen; or a wash composed of any material producing the desired result may be used. The washed or coated surface is then permitted to dry. However, I may omit this wash or coat if desired. This plain or prepared surface is then subjected to pressure in contact with the granulated or perforated side of the plate previously referred to.

Rolls, a press, or other means may be cmploycd to cause said plate to imprint its granulated side in reverse upon said prepared surface. The latter is thereby formed with small depressions corresponding to the projections of the plate, and the remaining portions of said prepared or plain surface are left in relief, therebyconstituting a finely granulated or abraded surface.

My next step is to rub over the surface thus prepared a crystal of nitrate of silver, the rub hing being continued until a small quantity of theuitrate of silver. is translierred-to the relief portions the surface.

Care is taken to prevent the nitrate of silver from touching the intaglio portions of the surface, and the cameo port-ions are alone I'.Il dered sensitive to the actinic action of light. An ordinary photographic negative of the object to be engraved is then presented to the said prepared photographic surface, and the latter is exposed to light through the said negative in the ordinary manner of exposure for a silver print.

The positive obtained is a facsimile copy of the object to be represented, but in the form of flue dots resembling mezzotint engraving. This print is then in turn photographed, and a final ncgativeis obtained in the proper state for the ordinary photo-relief process with gelatine and bichromate of ammonia.

It is obvious that according to the foregoing method I may reproduce a photographic i'ao simile of portraits, landscapes, architecture, flowers, machinery, and an objects from nature, and also copies of steel and wood eugraviugs, lithographs, drawings in wash, or monochrome paintings, sketches, and similar mat. ter.

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-- .l. The process of preparing negatives for photo-relief engraving consisting of the following steps: first, photographing a negative oi the object'to be engraved; second, printing a positive therefrom on a surface provided thereon; and, third, coating the upper porwith raised dots or points, which latter have tions only of said raised dots or points with their upper portions coated with a sensitizing .a sensitizing substance, substantially as set substance, while the remaining portion of the forth.

and,third,photographinganegative from such 1 In testimony that I claim the foregoing I 5 have hereunto set myhand this 13th day of December, 1879.

GEORGE CHARLES BELL. Witnesses:

HERMAN E. LONG, GILBERT J MoGiom.

surface is free from the sensitizing substance;

positive, substantially as set forth.

2. The process of preparing photographic surfaces consisting of the following steps: first, coating the surface with a compound or wash: second,'for1ning raised dots or points i 

